The Histopathology (Histology) section of the Laboratory of Pathology (LP) is a core facility devoted to supporting the clinical activities of LP. The laboratory processes a large variety of tissue specimens from NIH and non-NIH patients, including a wide variety of malignancies, AIDS-related diagnostic specimens, infections, and surveillance biopsies. This consists of accessioning human tissues removed at surgery or in clinics, processing the tissues, preparing and staining slides for microscopy by LP's pathologists, clinical fellows and residents. Pathology residents are trained by LP's Pathologists Assistants (PAs) in techniques of gross dissection and taught to evaluate large and small specimens in preparation for microscopic evaluation during Histology rotations. The Histology lab serves the Surgical Pathology, Hematopathology, Postmortem Pathology and Cytopathology sections as well as the Specialized / Molecular Diagnostics Unit. To date during this fiscal year, Histopathology processed more than 28,500 tissues blocks (a 12% increase from the previously reported year), 242,000 slides from microtomy and 43,250 special stains submitted to pathologists for diagnostic interpretation. After pathology diagnoses are rendered, Clinical Operations staff provide pathology reports to requesting clinicians internal and external to the NIH. During this period, LP's Pathologists Assistants performed and trained residents in gross analysis and selection of the most diagnostically relevant sections for tissues collected from over 12,175 inhouse biopsy and surgical tissues. So far this fiscal year, the laboratory processed over 132,000 consult slides and 3,450 blocks from over 4,250 cases that were submitted to LP's pathologists for clinical consultation or review for patients being admitted to the NIH Clinical Center or entry on protocol. Although more than 95% of effort is devoted to clinical duties, the Histology Laboratory also performs recuts of tissue blocks and does some routine staining for research projects in NCI by arrangement. This activity is coordinated with the tissue research request function of Clinical Operations.The Histology Lab does not conduct primary research but supports the activities of many investigators.